(a) Field of the Invention
This invention relates generally to a vibration absorbing structure of treadmill, and more particularly, to a newly invented vibration absorbing structure of treadmill that has good vibration absorbing capability and does not generate frictional noises.
(b) Description of the Prior Art
FIG. 1 shows the most commonly used vibration absorbing structure of treadmill. This structure consists of elastic units 10 installed between a treadmill base 11 and support board or treadmill framework 12. Though, in the beginning, this structure has good vibration absorbing capability, these elastic units 10 will develop elastic fatigue and may become broken after a duration of use. Moreover, when these elastic units 10 are damaged and needed to be replaced, the treading belt 13 and support board 12 have to be removed. From above mentioned, we can see that this structure is not structurally practical and does not provide sufficient accessibility.
FIGS. 2 and 3 show another patented vibration absorbing structure according to prior art. This structure consists of a base 14 with a spring holder 15, which allows its vertical rod 16 to insert with a connecting unit 17 in between. Its spring units 18 are installed between the spring holder 15 and vertical rod 16. These units 18 are fixed down by the two bolts 19 and extend from the bottom of spring holder 15 into the bottom parts of the vertical rods 16. When its treadmill base 20 is pressed and starts to vibrate, this will in turn cause the two vertical rods 16 to vibrate too. However, these two vertical rods 16 are held down only by the connecting unit 17 and two bolts 19 plus the fact that a person's body weight exerts scores of kilograms of force on the support board 20, these two vertical rods 16 can be held down effectively by this way are a question. In addition, the vibrations of the vertical rods 16 will cause the two bolts 19 to vibrate and these vibrations will in turn generate annoying noises due to the friction between these two bolts and the bolt holes 21 of the 14; also these vibrations will damage the two rods 19 too.